Circle cvi42

All CMR analysis was performed using commercially available software Circle CVI42 version 5.1 (Circle Cardiovascular Imaging Inc., Calgary, Canada). Left ventricular volumes and ejection fraction (EF) were analysed from short-axis cine images using standard methods. The presence of any scar or a significant perfusion defect (> 10% coverage of the left ventricle) was recorded by an expert with > 10 years of experience in CMR. These variables were treated as dichotomous variables.
For the four-chamber atrial volume analysis, the artificial intelligence module of CVI42 was used. Where necessary, further manual corrections were made. Figure 2 demonstrates how the atrial volumes were assessed at rest and peak myocardial hyperaemia.
Fig. 2

Overview of a case on how left and right atrial volumes were segmented at baseline and peak myocardial hyperemic state after adenosine administration. Both left and right atrial areas were recorded just before the mitral/tricuspid valve opening or ventricular end-systolic phase

Image post-processing was performed using Circle CVI42 (Circle Cardiovascular Imaging Inc, Alberta, CA). Left and right ventricular (LV and RV, respectively) end-diastole and end-systole endocardial and epicardial borders were traced to determine end-diastolic and end-systolic volumes (EDV and ESV respectively and myocardial mass. Ejections fraction (EF) were calculated by the equation ((EDV-ESV)/EDV)*100 and reported as percentages. Indexed EDV, ESV, and masses were calculated by dividing by body surface area (BSA). Volume and LV mass Z-scores were generated using published data. Z-scores between 2.0 and 3.5 were considered mildly enlarged, between 3.5 and 5.0 were considered moderately enlarged, and >5.0 were considered severely enlarged.(23 (link))
T2 and T1 mapping were analyzed in the respective CVI42 modules. Endocardial and epicardial borders were traced with 10% offset to ensure that only myocardium was included in tracings (Figure 1). T2 and native T1 values (msec) are reported as the mean value for the given basal, mid-ventricular, or apical slice.
T2 TSE, first pass perfusion, and inversion recovery imaging were reviewed to determine the presence of edema, perfusion defects, and LGE, respectively. All imaging analyses were performed by a single pediatric cardiologist with extensive training and experience in pediatric CMR (MPD).

Cine image analysis was performed using Circle CVI⁴² (version 5.13, Circle Cardiovascular Imaging, Inc., Calgary, AB, Canada). An assessment of the cardiac dimensions and function was performed on the short axis cine images. Endo- and epicardial contouring was performed using the automatic contouring algorithm, and manual adjustments were made, if necessary. End systolic and end diastolic volumes (ESV, EDV), stroke volume (SV), and LV ejection fraction (LVEF) were evaluated.

Image analysis and tissue tracking were performed with a CMR dedicated software for feature tracking (Circle CVI 42, Circle Cardiovascular Imaging Inc. Calgary, AB, Canada).
Endocardial and epicardial borders were manually delineated in end diastole and end systole in all short‐axis slices. End‐diastolic volume, end‐systolic volume, stroke volume, LV ejection fraction (EF) and cardiac output were calculated. Endocardial and epicardial borders were manually delineated in long‐axis two‐, three‐ and four‐chamber views in end diastole, and an automated propagation throughout the heart cycle was computed for each view (Fig. 2).
Endo‐ and epicardium of RVFW were manually delineated in the four‐chamber view, without including the septum, in end diastole and automatically propagated throughout the heart cycle (Fig. 2). Inadequate tracking for either the LV or the RV was manually corrected and recalculated. The presence of LGE was clinically assessed visually by experienced physician (E.O. >10 years of CMR experience).
All image analyses were performed blinded to clinical information by one observer (A.L.), with a second observer as adjudicator (E.O.) of the delineations.